doc: port old docs for Array#indexOf, update examples slightly
doc: port old docs for Array#indexOf, update examples slightly

ridixcr/prototype,baiyanghese/prototype,ShefronYudy/prototype,lamsieuquay/prototype,sdumitriu/prototype,ldf7801528/prototype,292388900/prototype,292388900/prototype,ldf7801528/prototype,sdumitriu/prototype,sstephenson/prototype,leafo/prototype,loduis/prototype,Jiasm/prototype,Jiasm/prototype,erpframework/prototype,ldf7801528/prototype,ridixcr/prototype,baiyanghese/prototype,ridixcr/prototype,lamsieuquay/prototype,fashionsun/prototype,fashionsun/prototype,Jiasm/prototype,loduis/prototype,sdumitriu/prototype,ShefronYudy/prototype,loduis/prototype,sstephenson/prototype,erpframework/prototype,Gargaj/prototype,ShefronYudy/prototype,Gargaj/prototype,Gargaj/prototype,292388900/prototype,leafo/prototype,lamsieuquay/prototype,sstephenson/prototype,fashionsun/prototype,erpframework/prototype